Chi-Square Problems

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An investigator observes that when pure-breeding long-wing Drosophila are mated with pure-breeding short-wing flies, the F1 offspring have an intermediate wing length.

 When several intermediate-wing length flies are allowed to interbreed the following results are obtained:

                         Observed

                        230 long wings

                        510 intermediate length wings

                        260 short wings 

1. What is the genotype of the F1 intermediate-wing length flies?
2. Write a null hypothesis describing the mode of inheritance of wing length in Drosophila.
3. Calculate the Chi-Square.
4. What degree of freedom do you use?
5. What is the probability value for these data?
6. According to the probability value, can you accept or reject the null hypothesis and explain why.